import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Solution2 {
    public static void main(String[] args) {
        String s = "barfoothefoobarman";
        String[] words = {"foo","bar"};
        List<Integer> ret = findSubstring(s,words);
        for(Integer i : ret) {
            System.out.println(i);
        }

    }
    public static List<Integer> findSubstring(String s, String[] words) {
        List<Integer> ret = new ArrayList<>();
        Map<String,Integer> hash1 = new HashMap<>();
        for(String str : words) {
            hash1.put(str,hash1.getOrDefault(str,0) + 1);
        }
        int len = words[0].length();
        int m = words.length;
        for(int i = 0; i < len; i++) {
            Map<String,Integer> hash2 = new HashMap<>();
            for(int left = i, right = i, count = 0; right <= s.length() - len; right += len) {
                //1.进窗口
                String in = s.substring(right, right + len);
                hash2.put(in, hash2.getOrDefault(in, 0) + 1);
                if(hash2.get(in) <= hash1.getOrDefault(in, 0)) {
                    count++;
                }
                //2.出窗口
                if(right - left + 1 > m * len) {
                    String out = s.substring(left, left + len);
                    if(hash2.get(out) <= hash1.getOrDefault(out, 0)) {
                        count--;
                    }
                    hash2.put(out,hash2.get(out) - 1);
                    left += len;
                }
                //3.更新结果
                if(count == m) {
                    ret.add(left);
                }
            }
        }
        return ret;
    }
}